New process for removing air and packaging an object, compressing the packaging material from the outside with external pressure rather than a vacuum

ABSTRACT

This invention is a novel process for skin packaging, and is an addition to the usual vacuum packaging processes. Instead of the skin being pushed down on to the object being sealed, by atmospheric air pressure created by a partial vacuum under the skin, it is instead pushed down on the object being sealed by increased external pressure. Both use the same difference between the outer air pressure and the inner air pressure. This difference in how the pressure differences are obtained, however, changes many of the procedures, and some of the results. There are many new opportunities opened up by this new process that can only be determined by further studies and experimentation.  
     Some of the advantages of my process are:  
     In the continuous tube packaging process there is no need to have a vacuum cavity or vacuum tubes. You simply apply pressure on the top with a hard platen underneath, seal the end, remove the pressure, flow the next package through and repeat.  
     When sealing semi-rigid containers you do not have to insert and remove the vacuuming tubes or vacuuming container as you do with the vacuuming process.  
     It also makes possible the use of re-sealable bags which can later be opened without destroying the packaging.

BACKGROUND OF THE INVENTION

[0001] The field of endeavor of this invention is packaging an object in an air- and water-tight container. The usual embodiment is vacuum sealing where part of the air surrounding the object in a flexible air and water tight container is removed by a vacuum pump and then the area of the air-withdrawal is sealed, usually with heat. The partial vacuum (reduced pressure) between the membrane and the object inside allows the atmospheric pressure to force the flexible container tightly around the object and cling to it by the atmospheric pressure.

[0002] The vacuum does not suck the air out. The vacuum pump produces a region of lower pressure and the atmospheric pressure pushes the membrane onto the article being packaged, thus pushing the air out. It is important to understand the correct physics of the process, because understanding my new process depends on this understanding. It is only with this understanding that my new process can be truly evaluated.

[0003] Kyle, U.S. Pat. No. 4,162,599 53/77, one of the earlier patents in vacuum packaging addressed two issues. The first was keeping the vacuuming channels open during the evacuation, and then sealing off the surface of the article (often food). The second was preventing the release of areas of high pressure within the food (in this case gas pockets in cheese, or juices in meat). They evacuated both under the flexible layer, and between the flexible layer and a rigid top plate. Though the method involved some differences in the pressure of the two layers in the packaging, it was still a vacuuming process. My process, on the other hand, involves not lowering the pressure inside but rather expelling the gasses by increasing the pressure outside. This has several advantages. One, it is much simpler. Two, in pressing the air out you do not release any fluids or entrained gas. Three, when you increase the external pressure rather than vacuuming it out, you do not close as many exit channels as you do by suction. Forth the biggest advantage is that you can use a bag open at one end with a ziploc, or similar seal. The ziploc seal is placed very close to the opening of the pressure container. The seal is closed when the gases have been expelled, and the outer container is removed This enables you to use externally sealed bags. These can later be opened and resealed, such as freezer packages, where you remove part of the contents, which you can later reseal or leave with some of the air in it. This is particularly convenient for articles such as cheese which are usually not all used at the same time. After the customer has taken out what she needs, she can simply seal the bag again and have a watertight container. There is no need to transfer it to another container with an air seal.

PRIOR ART

[0004] Skin tight packaging of food and other items is almost always done by vacuuming the air out and thus forcing the flexible skin down onto the object that one wishes to skin package by atmospheric pressure. Of course if you want to get rid of air between two surfaces, the natural thing to do is vacuum it out. But from the standpoint of physics, you do not vacuum the air out. You do not literally pull the air out. What really happens is that the pressure of the atmosphere pushes the two surfaces together and expels the air. It is, in fact, the differential pressure you produce between the air between the two surfaces and the atmosphere. You can produce the same effect by increasing the pressure outside the two surfaces. We do not suck the air out. We remove some air and the atmosphere pushes the two surfaces together. You can equally well produce the pressure differential by increasing the outside pressure. Similarly you can skin package a product just as easily by increasing the outside pressure. For some reason this does not seem to have been done commercially at all. I have searched the patent base for pressure packages. The only ones I could find were the patents listing “vacuum AND pressure” packaging:

[0005] Nielsen; Broder, U.S. Pat. No. 4,853,374, 53/434 repressurizes the chamber to press the article against the chamber, but then vacuums out more air. There is never any positive pressure applied.

[0006] Areblom, Rogberg, U.S. Pat. No. 4,757,669, 53/512 have a system for packaging garment or large items like sleeping bags, by putting an empty stretchable tube open to the atmospheric air that expands when the item is in the vacuum. They create a difference in pressure between the inner tube (atmospheric pressure) and the vacuum chamber, but no larger than atmospheric pressure. So again this is not a positive pressure device.

[0007] Segota, U.S. Pat. No. 4,922,686, 53/434 have a system of partially repressurizing the package after commencement of evacuation, preferable two times, but again it is not a positive pressure device, it merely decreases the vacuum and then increases it.

[0008] Chesterfield et all, U.S. Pat. No. 5,664,408, 53/512 seems closest to my invention in that external mechanical pressure is applied to the soft article being packaged while the interior is vacuumed. But one, the pressure is applied externally. Two, it is applied mechanically, and not through increased air pressure. Three, it is confined to a fixed external box representing the desired external form. And lastly, unlike my process, it also involves vacuum as well as pressure.

[0009] Kai, et al, U.S. Pat. No. 5,894,929, 6/524.8 also has some differential pressures in their patents, but they are all vacuum created., or created by the sterilization heat and vented to the outside.

[0010] In summary, I was unable to find any patents where the pressure to collapse the pocket around the article was produced by outside pressure.

[0011] There are two areas where external pressure is used: injections molding, and blow molding. In injection molding the material is pressured into the mold after it has been softened. This clearly is the use of positive pressure. The other is blow molding in which the material is introduced in a liquid state and then blown against the cavity walls with positive air pressure. Neither of these processes is a packaging process in which the article is covered with a thin film that protects the object as well as sealing the object. The whole processes are entirely different.

BRIEF SUMMARY OF THE INVENTION

[0012] A process is presented, where the pressure differential created by vacuuming the space to be evacuated is replaced by a positive pressure on the outside of the sealing layer, so that the air is expelled with positive pressure rather than extracted by pressure created by a relative vacuum inside the sealing layer.

DETAILED DESCRIPTION OF THE INVENTION

[0013] My invention is primarily in the art of skin packaging, though “soft packaging” is also included.

[0014] 1^(st) embodiment: It consists of an outer container for pressurizing the object and a flexible inner container, which will become the packaging material. This outer container may be a rigid box or a non-stretchable flexible container. The inner container, in this embodiment is a ziploc or similar bag. The object to be sealed may or may not be attached to a somewhat rigid base. The object to be sealed is placed in a zip-lock bag or other sealable container with the sealable container open. This object and it's container is then placed inside the outer container with the opening part outside the outer container, with enough room for the outer container to temporarily mechanically seal the neck of the inner container. The outer container is pressurized to perhaps 1, 2, 10 psi or more. Since the inner container is open to the atmosphere, this squeezes the inner container down around the object and squeezes the air out in the same way that a vacuum does. Then the zip-lock is closed and the other inner seal is opened, and the object and its formed skin are removed from the outer container. It is not the vacuum that forces the inner bag to collapse, but the pressure differential between the inner bag and the outer bag that expels the air, and forces the inner bag to collapse.

[0015] What are the similarities and difference from these two methods of collapsing the bag around the object?

[0016] Similarities:

[0017] 1. Both methods force the inner bag to collapse tightly around the object.

[0018] 2. Both techniques will form the inner bag just as tightly around the object.

[0019] Differences:

[0020] 1. In the open bag process you do not need to insert and remove the vacuum tubes.

[0021] 2. In my technique the final skin package will not be as vulnerable to very small leaks, leaks through the plastic bag, or migration through the wall of gases and plasticizers as the pressure inside of the bag is the same as outside the bag, while with vacuum processing there are large pressure differences between the internal pressure and the atmosphere.

[0022] 3. There will be little out-gassing from the object, which in the case if cheese and some other foods may be an advantage.

[0023] 4. The customer will be able to open and remove material from the package, and reseal it, though you will lose some of the cling. He will not have to transfer the object (food?) to a separate bag, to keep it from drying out. This will be a great convenience to consumers and is a natural brand extension for ziploc or others.

[0024] 4. You will not get as complete removal of gasses in my method, as for example when you want to remove the O₂ from the object packaged. However, you can get rid of undesirable gases by filling the inner plastic with an inert gas or CO₂, waiting for diffusion between the gas and the object, and pressing it out. And you can repeat the cycle to expel even more of the gas.

[0025] 5. Other differences will be discovered, some more favorable, other less favorable.

[0026] 6. In many ways it is easier to apply pressure than to reduce pressure, but again this will vary with the your goal. Where you want a vacuum you will use a vacuum method, but where you only want to remove the air under the sealing layer, you may want to use pressure.

[0027] Never-the-less, this technique is original and non-obvious since no one seems to have used it before, at least not in a systemic way.

[0028] The original embodiment was designed for sealing ziploc bags and other bags with an external seal. In this embodiment the bag is filled with the object to be entrained. The bag is left open. The bag is placed with the bag-lock open, just outside of the pressure chamber. The pressure chamber has a flat rigid edge with a soft seal close to the external opening that helps retain the inner pressure in the pressure container but lets the excess air out of the inner bag. The pressure chamber is filled with compressed air. The bag is sealed and the pressure chamber depressurized and removed.

[0029] There are at least three other embodiments of this process: One is skin packaging in other than open bags such as a continuous tube, situations where ordinarily vacuum is currently used to expel the air between the flexible layer and the article that is to be sealed. In the pressure process, you can simply press the air out and seal the tube and flow to the next package. There are a number of ways to produces the pressure greater than atmospheric. A non-stretchable container may be placed over the object and packaging with the continuous tube sealed on one side from the previous item and not sealed where it surrounds the new item. The packaging is pressed onto the item by increase in the container pressure, sealed, and then the external container is opened. It is also possible to apply pressure mechanically with a flexible container, but the seal will not be as good as with air pressure.

[0030] The second is when the packaged material is a preformed fairly rigid cavity and is to be sealed at the top, with a flexible membrane. The mechanical details will be different but it will be sealed with positive pressure.

[0031] The third embodiment is “soft” packaging, where the material is easily compressible but also easily damaged. It is hard to determine in advance, in which of these areas the manufacturer will prefer pressure over vacuum packaging. Still in these areas, pressure packaging is new and non-obvious.

[0032] I expect to have many specific embodiments, which I am working on and documenting. 

I claim:
 1. A process of skin packaging, where the pressure difference necessary to press the packaging material down on the packed material is produced by positive pressure from outside of the package, rather than reducing the pressure inside the package. a. The process defined in claim 1, where the process is skin packaging such as a continuous tube, situations where ordinarily vacuum is currently used to expel the air between the flexible layer and the article that is to be sealed is replaced by a pressure process; where you can simply press the air out and seal the tube and flow to the next package; and there are a number of ways to produces the pressure greater than atmospheric, such as a non-stretchable container may be placed over the object and packaging with the continuous tube sealed on one side from the previous item and not sealed where it surrounds the new item, and the packaging is pressed onto the item by increase in the container pressure sealed and then the pressure container opened; and where it is also possible to apply pressure mechanically with a flexible container, but the seal will not be as good as with air pressure. b. The process defined in claim 1, where the package is within a preformed fairly rigid cavity, and is to be sealed at the top with a flexible membrane, and the pressure difference is produced from the outside with a compressed gas, in an outer container. c. The process defined in claim 1, for “soft packaging”, where the object is easily compressible, but easily damaged, and requires no vacuuming tube, only external pressure from a surrounding container. d. The process defined in claim 1, where the inner bag is open but sealable with a ziploc or similar closure, which requires no vacuum tube that has to be removed as you seal the container, only a temporary seal at the opening. 